The field of this invention is building security and more specifically providing a single means for signalling an alarm if a window or door is opened, the foregoing being a first function and a second function being the provision of a mechanical means such as a bar to prevent the window or door from being opened.
An example of the prior art is U.S. Pat. No. 4,553,134 which teaches apparatus for signalling an alarm; the apparatus comprises a telescoping rod that is positioned inside a window casing and if the rod is moved, e.g., by a burglar, then an alarm will be actuated. U.S. Pat. No. 4,553,134 shows an electrical alarm system comprising a rod inserted into a tube in telescope fashion, the rod having a compression spring for removably affixing the rod and tube within the casing of a window or a door. The rod has sensor means connected in a closed circuit to an alarm means and when the spring loaded rod and tube assembly is jarred or moved, then the sensor means opens or closes the circuit and the alarm means sounds. While this patent teaches an alarm function, it does not teach the separate and important function of having a bar that will mechanically resist the opening of the window or door.
Prior art patents include those patents cited as references for U.S. Pat. No. 4,553,134. None of these prior art patents teach a dual function apparatus of the present invention.